/*
 * This source file is part of ARK
 * For the latest info, see https://github.com/ArkNX
 *
 * Copyright (c) 2013-2019 ArkNX authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"),
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

// the basic code from https://github.com/ylywyn/code/blob/7a7ee609ce/cpp/hash/MurmurHash.h

#pragma once

#include "base/AFPlatform.hpp"
#include "base/AFMacros.hpp"

namespace ark {

class AFMurmurHash
{
public:
    static void MurmurHash3_x86_32(const void* key, int len, uint32_t seed, void* out)
    {
        const uint8_t* data = (const uint8_t*)key;
        const int nblocks = len / 4;

        uint32_t h1 = seed;

        const uint32_t c1 = 0xcc9e2d51;
        const uint32_t c2 = 0x1b873593;

        //----------
        // body

        const uint32_t* blocks = (const uint32_t*)(data + nblocks * 4);

        for (int i = -nblocks; i; i++)
        {
            uint32_t k1 = getblock(blocks, i);

            k1 *= c1;
            k1 = ROTL32(k1, 15);
            k1 *= c2;

            h1 ^= k1;
            h1 = ROTL32(h1, 13);
            h1 = h1 * 5 + 0xe6546b64;
        }

        //----------
        // tail

        const uint8_t* tail = (const uint8_t*)(data + nblocks * 4);

        uint32_t k1 = 0;

        switch (len & 3)
        {
            case 3:
                k1 ^= tail[2] << 16;
            case 2:
                k1 ^= tail[1] << 8;
            case 1:
                k1 ^= tail[0];
                k1 *= c1;
                k1 = ROTL32(k1, 15);
                k1 *= c2;
                h1 ^= k1;
        };

        //----------
        // finalization

        h1 ^= len;

        h1 = fmix(h1);

        *(uint32_t*)out = h1;
    }

    //-----------------------------------------------------------------------------

    void MurmurHash3_x86_128(const void* key, const int len, uint32_t seed, void* out)
    {
        const uint8_t* data = (const uint8_t*)key;
        const int nblocks = len / 16;

        uint32_t h1 = seed;
        uint32_t h2 = seed;
        uint32_t h3 = seed;
        uint32_t h4 = seed;

        const uint32_t c1 = 0x239b961b;
        const uint32_t c2 = 0xab0e9789;
        const uint32_t c3 = 0x38b34ae5;
        const uint32_t c4 = 0xa1e38b93;

        //----------
        // body

        const uint32_t* blocks = (const uint32_t*)(data + nblocks * 16);

        for (int i = -nblocks; i; i++)
        {
            uint32_t k1 = getblock(blocks, i * 4 + 0);
            uint32_t k2 = getblock(blocks, i * 4 + 1);
            uint32_t k3 = getblock(blocks, i * 4 + 2);
            uint32_t k4 = getblock(blocks, i * 4 + 3);

            k1 *= c1;
            k1 = ROTL32(k1, 15);
            k1 *= c2;
            h1 ^= k1;

            h1 = ROTL32(h1, 19);
            h1 += h2;
            h1 = h1 * 5 + 0x561ccd1b;

            k2 *= c2;
            k2 = ROTL32(k2, 16);
            k2 *= c3;
            h2 ^= k2;

            h2 = ROTL32(h2, 17);
            h2 += h3;
            h2 = h2 * 5 + 0x0bcaa747;

            k3 *= c3;
            k3 = ROTL32(k3, 17);
            k3 *= c4;
            h3 ^= k3;

            h3 = ROTL32(h3, 15);
            h3 += h4;
            h3 = h3 * 5 + 0x96cd1c35;

            k4 *= c4;
            k4 = ROTL32(k4, 18);
            k4 *= c1;
            h4 ^= k4;

            h4 = ROTL32(h4, 13);
            h4 += h1;
            h4 = h4 * 5 + 0x32ac3b17;
        }

        //----------
        // tail

        const uint8_t* tail = (const uint8_t*)(data + nblocks * 16);

        uint32_t k1 = 0;
        uint32_t k2 = 0;
        uint32_t k3 = 0;
        uint32_t k4 = 0;

        switch (len & 15)
        {
            case 15:
                k4 ^= tail[14] << 16;
            case 14:
                k4 ^= tail[13] << 8;
            case 13:
                k4 ^= tail[12] << 0;
                k4 *= c4;
                k4 = ROTL32(k4, 18);
                k4 *= c1;
                h4 ^= k4;

            case 12:
                k3 ^= tail[11] << 24;
            case 11:
                k3 ^= tail[10] << 16;
            case 10:
                k3 ^= tail[9] << 8;
            case 9:
                k3 ^= tail[8] << 0;
                k3 *= c3;
                k3 = ROTL32(k3, 17);
                k3 *= c4;
                h3 ^= k3;

            case 8:
                k2 ^= tail[7] << 24;
            case 7:
                k2 ^= tail[6] << 16;
            case 6:
                k2 ^= tail[5] << 8;
            case 5:
                k2 ^= tail[4] << 0;
                k2 *= c2;
                k2 = ROTL32(k2, 16);
                k2 *= c3;
                h2 ^= k2;

            case 4:
                k1 ^= tail[3] << 24;
            case 3:
                k1 ^= tail[2] << 16;
            case 2:
                k1 ^= tail[1] << 8;
            case 1:
                k1 ^= tail[0] << 0;
                k1 *= c1;
                k1 = ROTL32(k1, 15);
                k1 *= c2;
                h1 ^= k1;
        };

        //----------
        // finalization

        h1 ^= len;
        h2 ^= len;
        h3 ^= len;
        h4 ^= len;

        h1 += h2;
        h1 += h3;
        h1 += h4;
        h2 += h1;
        h3 += h1;
        h4 += h1;

        h1 = fmix(h1);
        h2 = fmix(h2);
        h3 = fmix(h3);
        h4 = fmix(h4);

        h1 += h2;
        h1 += h3;
        h1 += h4;
        h2 += h1;
        h3 += h1;
        h4 += h1;

        ((uint32_t*)out)[0] = h1;
        ((uint32_t*)out)[1] = h2;
        ((uint32_t*)out)[2] = h3;
        ((uint32_t*)out)[3] = h4;
    }

    static void MurmurHash3_x64_128(const void* key, const int len, const uint32_t seed, void* out)
    {
        const uint8_t* data = (const uint8_t*)key;
        const int nblocks = len / 16;

        uint64_t h1 = seed;
        uint64_t h2 = seed;

        const uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
        const uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);

        //----------
        // body

        const uint64_t* blocks = (const uint64_t*)(data);

        for (int i = 0; i < nblocks; i++)
        {
            uint64_t k1 = getblock(blocks, i * 2 + 0);
            uint64_t k2 = getblock(blocks, i * 2 + 1);

            k1 *= c1;
            k1 = ROTL64(k1, 31);
            k1 *= c2;
            h1 ^= k1;

            h1 = ROTL64(h1, 27);
            h1 += h2;
            h1 = h1 * 5 + 0x52dce729;

            k2 *= c2;
            k2 = ROTL64(k2, 33);
            k2 *= c1;
            h2 ^= k2;

            h2 = ROTL64(h2, 31);
            h2 += h1;
            h2 = h2 * 5 + 0x38495ab5;
        }

        //----------
        // tail

        const uint8_t* tail = (const uint8_t*)(data + nblocks * 16);

        uint64_t k1 = 0;
        uint64_t k2 = 0;

        switch (len & 15)
        {
            case 15:
                k2 ^= uint64_t(tail[14]) << 48;
            case 14:
                k2 ^= uint64_t(tail[13]) << 40;
            case 13:
                k2 ^= uint64_t(tail[12]) << 32;
            case 12:
                k2 ^= uint64_t(tail[11]) << 24;
            case 11:
                k2 ^= uint64_t(tail[10]) << 16;
            case 10:
                k2 ^= uint64_t(tail[9]) << 8;
            case 9:
                k2 ^= uint64_t(tail[8]) << 0;
                k2 *= c2;
                k2 = ROTL64(k2, 33);
                k2 *= c1;
                h2 ^= k2;

            case 8:
                k1 ^= uint64_t(tail[7]) << 56;
            case 7:
                k1 ^= uint64_t(tail[6]) << 48;
            case 6:
                k1 ^= uint64_t(tail[5]) << 40;
            case 5:
                k1 ^= uint64_t(tail[4]) << 32;
            case 4:
                k1 ^= uint64_t(tail[3]) << 24;
            case 3:
                k1 ^= uint64_t(tail[2]) << 16;
            case 2:
                k1 ^= uint64_t(tail[1]) << 8;
            case 1:
                k1 ^= uint64_t(tail[0]) << 0;
                k1 *= c1;
                k1 = ROTL64(k1, 31);
                k1 *= c2;
                h1 ^= k1;
        };

        //----------
        // finalization

        h1 ^= len;
        h2 ^= len;

        h1 += h2;
        h2 += h1;

        h1 = fmix(h1);
        h2 = fmix(h2);

        h1 += h2;
        h2 += h1;

        ((uint64_t*)out)[0] = h1;
        ((uint64_t*)out)[1] = h2;
    }

    static void MurmurHash2(const void* key, int len, void* out)
    {
        uint32_t h, k;

        h = 0 ^ len;
        const uint8_t* data = (const uint8_t*)key;
        while (len >= 4)
        {
            k = data[0];
            k |= data[1] << 8;
            k |= data[2] << 16;
            k |= data[3] << 24;

            k *= 0x5bd1e995;
            k ^= k >> 24;
            k *= 0x5bd1e995;

            h *= 0x5bd1e995;
            h ^= k;

            data += 4;
            len -= 4;
        }

        switch (len)
        {
            case 3:
                h ^= data[2] << 16;
            case 2:
                h ^= data[1] << 8;
            case 1:
                h ^= data[0];
                h *= 0x5bd1e995;
        }

        h ^= h >> 13;
        h *= 0x5bd1e995;
        h ^= h >> 15;

        *(uint32_t*)out = h;
    }

private:
    inline static uint32_t ROTL32(uint32_t x, int8_t r)
    {
#ifdef ARK_PLATFORM_WIN
        return _rotl(x, r);
#else
        return (x << r) | (x >> (32 - r));
#endif
    }

    inline static uint64_t ROTL64(uint64_t x, int8_t r)
    {
#ifdef ARK_PLATFORM_WIN
        return _rotl64(x, r);
#else
        return (x << r) | (x >> (64 - r));
#endif
    }

    static uint32_t getblock(const uint32_t* p, int i)
    {
        return BYTESWAP32(p[i]);
    }

    static uint64_t getblock(const uint64_t* p, int i)
    {
        return BYTESWAP64(p[i]);
    }

    static uint32_t fmix(uint32_t h)
    {
        h ^= h >> 16;
        h *= 0x85ebca6b;
        h ^= h >> 13;
        h *= 0xc2b2ae35;
        h ^= h >> 16;

        return h;
    }

    static uint64_t fmix(uint64_t k)
    {
        k ^= k >> 33;
        k *= BIG_CONSTANT(0xff51afd7ed558ccd);
        k ^= k >> 33;
        k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
        k ^= k >> 33;

        return k;
    }
};

} // namespace ark
